The introduction of natural-gas-powered thermoelectricity into the Brazilian generation sector can be considered as a very complex energy, economic, regulatory and institutional revision. Brazil is a country with very specific characteristics in electricity generation, as approximately 80% of the generating capacity is based on hydroelectricity, showing strong dependency on rain and management of water reservoirs. A low rate of investment in the Brazilian Electricity Industry in the period of 1995-2000, associated with periods of low rainfall, led to a dramatic lowering of the water stocks in the reservoirs. With this scenario and the growing supply of natural gas, both from within Brazil and imported, natural gas thermal electric plants became a good option to diversify the electrical supply system. In spite of the Brazilian Government's efforts to install such plants, the country was faced with severe electricity rationing in 2001. The objective of this work is to show the need to continue with the implementation of natural gas thermal electricity projects, in a manner that allows flexibility and guarantees greater working reliability for the entire Brazilian electricity sector. Taking into account the world trend towards renewable energy, the perspectives of usage of biofuels in the Brazilian Energy Matrix and in electrical energy generation are also analyzed. The very issue of electrical power efficiency in Brazil and its challenges and strategic proposals from the standpoint of Government Programs and results provided so far are presented. The technological constraints in order to put on stream the thermal electric plants are also analyzed. The article concludes with a positive perspective of the usage of natural gas as to be the third pillar in the Brazilian Energy Matrix for the years to come. (C) 2007 Published by Elsevier Ltd.